The invention pertains to a method and an automatic device for the sharp separation and removal of layers of fluids from a container by way of the container headspace and for the automatic cleaning of the container. The condition of stratified layers of fluid in a container should be understood to include situations in which a layer of sediment or lees has formed and is overlaid by a layer of clear fluid, and the two layers are separated by a stable and well-defined interface.
The Kitzinger Weinbuch, issue 1981, page 56, shows a complete wine siphon for the withdrawal of wine from its yeast layer in a glass barrel after fermentation. The suction pipe dipped into the wine via an opening in the head space of the barrel sealed by a rubber plug is connected outside the barrel to a hose. The separation between wine and yeast is effected by placing the lower end of the suction pipe close to the interface between clear wine and wine yeast and, after lowering the suction pipe during the final withdrawal phase, the wine withdrawn will be controlled by visual inspection to indicate when no clear wine is left in the barrel.
Wine cellars are confronted in principle with the same problem, but to a larger extent; and the means known heretofore to solve the problem are similar to those as described before. Here, too, containers of stratified fluids are to be found. The sediment that has collected in the barrels is overlaid by a layer of clear wine. The emptying of a barrel of wine is accomplished by way of an opening in the headspace of the barrel. The clear wine is withdrawn first and then the lees, that is, the layer of wine containing the sedimented material. During the withdrawal of the clear wine an effort is made, of course, to secure a maximum volume of the clear wine. A suction apparatus is dipped into the clear wine by way of an opening in the headspace of the barrel and lowered to a position close to the interface between the clear wine and the sediment. The correct placement of the apparatus so as to permit only clear wine to be removed and to avoid disturbing the sediment is controlled by a visual inspection of the wine as it is removed and as it passes through a viewing glass in the line. After a number of wine barrels have been so emptied, one gains some empirical estimate of the amount of the sediment present and, thus, the operation may be simplified by installing a spacer at the operation may be simplified by installing a spacer at the tip of the suction apparatus. The spacer touches the bottom of the barrel and keeps the inlet of the suction apparatus at the correct distance from the surface of the sediment so that the positioning of the suction apparatus continues to be the same from barrel to barrel. This well-known method of emptying barrels as well as the equipment used to accomplish it have shortcomings and disadvantages. It succeeds as an automatic method for emptying wine barrels only when the amounts of sediment that are formed are exactly the same from barrel to barrel. If there are variations in the development of the sediment,whether because of differences in the amount of sediment that is formed or because of differences in the form of the bottom of the barrels, the fixed position of the inlet of the suction apparatus will lead either to the drawing up of some of the sediment or to an incomplete removal of the clear wine. Furthermore, at the end of the removal of the clear wine or at the end of the removal of the wine that is full of sediment, the pick-up of air into these fluids can be held to a minimum only if the operator shuts down the operation at exactly the right moment. The contamination of wine with air has a detrimental effect on its stability. The layer of wine that is full of sediment is usually not discarded but is further processed for the recovery of the wine. Here also the pick-up of air at the end of the removal from the barrel should be kept to a minimum.